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The Mahimahi Coryphaena hippurus has excellent potential for aquaculture due to its fast growth, good food conversion ratio, high fecundity with natural captive spawns, and high price. Using current technology, three crops a year could yield 288,000 kg/ha of water/yr with a potential profit of US $1,280,000/ha water/yr.
Hatchery methods are now adequate for pilot-scale production, and two venture capital companies are pursuing this course. Significant improvement could be made in egg quality, plankton nutrition, plankton substitutes, disease control, reduced aggression, and weaning feeds. More research is needed to learn about digestive physiology, weaning behavior, and the effects of crowding on mahimahi health. Hatchery production is limited most often by the amount of grown out Artemia or yolk-sac mahi larvae provided for postlarval feeding. Problems that occur at the broodstock, hatching, first feeding, second feeding, third feeding, weaning, and early juvenile stages are discussed.
Using the current technology, the cost of post-hatchery mahimahi is 33 cents per fry. This cost could be reduced to 6 cents per fry by successfully (consistently) weaning postlarvae from live feeds by 25 days. 相似文献
Hatchery methods are now adequate for pilot-scale production, and two venture capital companies are pursuing this course. Significant improvement could be made in egg quality, plankton nutrition, plankton substitutes, disease control, reduced aggression, and weaning feeds. More research is needed to learn about digestive physiology, weaning behavior, and the effects of crowding on mahimahi health. Hatchery production is limited most often by the amount of grown out Artemia or yolk-sac mahi larvae provided for postlarval feeding. Problems that occur at the broodstock, hatching, first feeding, second feeding, third feeding, weaning, and early juvenile stages are discussed.
Using the current technology, the cost of post-hatchery mahimahi is 33 cents per fry. This cost could be reduced to 6 cents per fry by successfully (consistently) weaning postlarvae from live feeds by 25 days. 相似文献
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Syd Kraul Alan Nelson Karen Brittain Harry Ako Amy Ogasawara 《Journal of the World Aquaculture Society》1992,23(4):299-306
Live hatchery feeds were assayed for fatty acids (FA), amino acids (AA), and their ability to support growth and survival of larval and postlarval mahimahi Coryphaena hippurus at two different hatchery stages. Euterpina acuritrons copepods (C), mahimahi yolk-sac larvae (YSL), Artemia parthenogenica brine shrimp nauplii (BSn), A. parthenogenica juveniles (BSj), and Brachionus plicatilis rotifers (R) were assayed, using several enrichment media. There was little difference in AAs among feeds.
Levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were about 10 times higher in YSL than in their feeds. This explains previous findings where first stage larval survival (0–9 days) was not affected by feed HUFA levels. Second stage survival was significantly higher when larvae were fed copepods. Enrichment with 100 ppm SuperSelco greatly improved the survival of larvae that were fed brine shrimp. The even higher omega-3 fatty acids found in copepods appear to be important for survival of larvae under more stressful conditions.
Brine shrimp juveniles enriched with SuperSelco are a good food for postlarval mahimahi. Yolksac larvae of mahimahi are an even better food, promoting faster growth at less cost, for large scale mahimahi aquaculturists. Different batches of yolksac mahimahi larvae varied by a factor of 10 in their concentration of DHA, but always had the highest level of DHA as much as 40% of total fatty acids (FAs). These "high HUFA" batches of YSL also had the highest levels of EPA and total fatty acids. The data suggest that climate and broodstock age may have considerable influence on larval nutrition. 相似文献
Levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were about 10 times higher in YSL than in their feeds. This explains previous findings where first stage larval survival (0–9 days) was not affected by feed HUFA levels. Second stage survival was significantly higher when larvae were fed copepods. Enrichment with 100 ppm SuperSelco greatly improved the survival of larvae that were fed brine shrimp. The even higher omega-3 fatty acids found in copepods appear to be important for survival of larvae under more stressful conditions.
Brine shrimp juveniles enriched with SuperSelco are a good food for postlarval mahimahi. Yolksac larvae of mahimahi are an even better food, promoting faster growth at less cost, for large scale mahimahi aquaculturists. Different batches of yolksac mahimahi larvae varied by a factor of 10 in their concentration of DHA, but always had the highest level of DHA as much as 40% of total fatty acids (FAs). These "high HUFA" batches of YSL also had the highest levels of EPA and total fatty acids. The data suggest that climate and broodstock age may have considerable influence on larval nutrition. 相似文献
3.
Sanjay Gairola Arvind Bhatt Yanadayalan Govender Himansu Baijnath Şerban Procheş Syd Ramdhani 《Urban Forestry & Urban Greening》2013,12(3):315-322
Relatively few studies have investigated mistletoe infestation of tree species in urban settings, and even fewer considered infestation of alien tree species. Here, mistletoe infestation incidence and intensity were studied in Durban, South Africa. The relationship of infestation to tree CBH and height was examined in detail for the mistletoe species Erianthemum dregei. Although E. dregei is known to have a wide range of host taxa, we report E. dregei infestation on 27 new host species for the first time. E. dregei occurred on 30 host species with a preference for the alien host tree Melia azedarach in our study area. The relationship between infestation and CBH indicated that the trees (irrespective of species) of ≥200 cm were more susceptible to the mistletoe attack. The implications of this pattern, as well as those of high host diversity and especially of infestation of alien trees are discussed in a conservation perspective. 相似文献
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Nutritional Factors Affecting Stress Resistance in the Larval Mahimahi Coryphaena hippurus 总被引：1，自引：0，他引：1
Syd Kraul Karen Brittain Robert Cantrell Terri Nagao Amy Ogasawara Harry Ako Henry Kitagawa 《Journal of the World Aquaculture Society》1993,24(2):186-193
Recent improvements in enriching Artemia make mahimahi culture possible without using copepods. Mahimahi survive better when cultured copepods Euterpina acutifrons are used, especially when the larvae are under stresses such as high stocking density, cold weather, or the rigors of metamorphosis. This study looked at some differences between copepods and enriched Artemia .This study tested stress resistance by holding postlarval (PL) mahimahi out of water in a hand net for varying periods of time. Recovery from this stress shock was higher in PLs whose diet was higher in docosahexaenoic acid (DHA). DHA appeared to play an important role in stress resistance. High eicosapentaenoate (EPA) or high HUFA did not confer stress resistance when DHA levels were low. Copepods contained higher levels of many essential amino acids in addition to higher levels of DHA compared with enriched brine shrimp.
Larvae sickened by disease appeared to lose fat, including DHA, but they conserved DHA relative to other fatty acids. Even when sick, mahimahi larvae fed a copepod diet resisted stress better than larvae fed an enriched brine shrimp diet.
Optimal Artemia enrichment levels of DHA for mahimahi have not been reached and this may explain why it has been difficult for others to raise this fish consistently.
E. acutifrons is relatively easy to culture, but may not be practical for commercial hatcheries, due to low yield (less than 10 g per 100 L per week). 相似文献
Larvae sickened by disease appeared to lose fat, including DHA, but they conserved DHA relative to other fatty acids. Even when sick, mahimahi larvae fed a copepod diet resisted stress better than larvae fed an enriched brine shrimp diet.
Optimal Artemia enrichment levels of DHA for mahimahi have not been reached and this may explain why it has been difficult for others to raise this fish consistently.
E. acutifrons is relatively easy to culture, but may not be practical for commercial hatcheries, due to low yield (less than 10 g per 100 L per week). 相似文献
5.
Naser Khan Ian Clark Nanthi Bolan Sebastian Meier Christopher P. Saint Miguel A. Sánchez-Monedero Syd Shea Johannes Lehmann Rongliang Qiu 《Journal of Soils and Sediments》2017,17(3):656-664
Purpose
The purpose was to develop a netbag technique suitable for burying biochar in a compost or composting medium, followed by its collection in a clean state (i.e., free of compost debris) without loss or damage, for physicochemical analyses. Collection in a clean state is required to ensure that the analytical data of various biochars are representative and comparable. Five criteria were identified to evaluate the suitability of netbag.Materials and methods
A small netbag (3.5?×?3.5 cm) was developed using nylon fabric (30-μm mesh) to contain ～1 g of biochar. A production system was developed to make 15 netbags per batch. Unlike commonly used litterbags, polypropylene was used to seal netbags. Two experiments were conducted in which three biochars, made from macadamia nutshell, hardwood shaving, and chicken litter, were co-composted with chicken manure and sawdust and also incubated with a chicken litter-based commercial compost. Biochars were added at the rates of 5 or 10 % in the co-composting and 10 or 20 % in the incubation experiments. The biochar-containing netbags were buried in the co-composting and incubation mediums for 133 days. Various physicochemical analyses were conducted with netbag-biochars and their compost mediums.Results and discussion
The netbags collected after both experiments showed no visible sign of degradation. The weight of netbag-biochars from co-composting and incubation systems did not reduce significantly over the experimental period, thereby indicating no loss of biochar. No visible evidence of entry of solid particles from compost medium was found on the netbag-biochars. Pretests indicated that the netbag and biochars absorbed pore solution from the medium. Findings showed that elements translocated between the netbag-biochar and compost medium. A colony of coccus bacteria was found on the surface of composted chicken litter biochar, denoting probable entry of bacteria from compost medium. Unlike conventional litterbags, the netbags were suitable for burying and extracting biochar in compost/composting mediums due to smaller size, smaller mesh, and strong sealing with polypropylene.Conclusions
The netbags addressed all the five criteria. Therefore, it was concluded that, in the co-compost or incubated-compost medium, the biochar retained in the netbag and the biochar mixed with the medium were exposed to a similar bio-oxidative environment, and netbag-biochar represents the biochar in the medium. This means that these netbags can be used as a convenient means to examine the effects of the composting process or incubation in compost on biochar.6.
An estimated 58 000 junvenile (0.3–8 g weight and 30–90 mm total length) grey mullet, Mugil cephalus, were propagated in 1980 for livebait trials for tuna fishing. High hatchery yields were obtained through the control of incident sunlight, feeding with cultured copepods, and frequent, vigorous cleaning of tanks. The best yields were about 1 kg/m3 per 4-month cycle. Growth data, survival, and yields are discussed, and hypotheses for the improved results are proposed. 相似文献
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